Polishing of metal articles, such as kitchen sinks, cookware, etc., is normally carried out under high speed conditions, up to 7,000 rpm, and with substantial pressure being applied by the polishing head to the metal workpiece. It is important in polishing metal articles to have a positive drive transmission between the driving source and the abrasive band to prevent slippage of the band during the high speed, high pressure operating conditions.
In the past, a typical polishing head has been composed of a central rotatable shaft with a rubber sleeve bonded to the shaft. The outer surface of the rubber sleeve has been provided with a series of circumferentially spaced, longitudinal slots that are cut at an angle to the radius of the sleeve. The abrasive band is manually installed on the rubber sleeve by twisting the sleeve in a direction to compress the slots, thereby reducing the external diameter of the sleeve, and then slipping the band over the compressed sleeve. Installation of the abrasive band is a very difficult operation, requiring considerable strength and dexterity, particularly when the polishing head is mounted vertically in a polishing machine. Depending on the particular article being polished, it is often necessary to replace the abrasive band numerous times during a working shift.
It is also known in the woodworking art to mount a sandpaper belt on an expandable hub, as shown in U.S. Pat. Nos. 1,395,468, 154,756, 1,570,166 and 2,083,793. In this type of construction, as described in the aforementioned patents, a tapered mandrel is inserted within an expandable hub, causing the hub to expand radially and grip the abrasive band. However, this type of mounting of the abrasive band, while operable under low speed conditions on wood, has not been successfully employed with high speed, high pressure metal polishing operations.